1. Field of the Invention
The present invention relates in general to top entry valves and pertains, more particularly, to an improved sealing arrangement for these types of valves.
2. Background Discussion
High performance valves, particularly those used at cryogenic temperatures require carefully fabricated gates and seats to assure proper closure of the valve without the likelihood of leakage. Because of the stringent requirements for such high performance valves, it is often necessary to have easy access to the gate and seats of the valve for repairs and other modifications. In this regard, refer to my previously granted U.S. Pat. No. 3,471,122, granted Oct. 7, 1969 for an illustration of a top entry valve that provides good accessibility to the valve components.
An object of the present invention is to provide an improved top entry valve.
Another object of the present invention is to provide an improved entry valve that may be constructed with an insulating cryogenic jacket for encapsulating the valve in a manner which permits access to the valve components without removal of the valve from the line. In such a construction the gate of the top entry valve is removable without destroying the jacket or without removing the body of the valve from the line.
Another object of the present invention is to provide an improved top entry valve with an improved valve seat construction.
A further object of the present invention is to provide an improved top entry gate valve particularly for cryogenic purposes and in which at least formed angular cross-sectioned deformable sealing member is carried by the gate and is adapted to engage a rigid seat in the valve.